hi,

i am reaching a little here, but...  it may be that these gold bumps mate with gold bumps on its mating board.  compressive forces (applied by fasteners?) maintain the connection.

some time back, an engineer at trw developed what turned out to be 'fuzz buttons'.  these were fine gold plated wires that were compressed into 'fuzz' in a cylinder.  they had some spring action to them.  they were used to interconnect die and components on to test fixtures.  the parts were pressed onto the test fixture that had the buttons built into the test adapters.  the parts were then pushed onto the buttons for the interconnect.  after testing the part was removed and replaced with another one.

phil

-----Original Message-----
From: Brooks,Bill [mailto:[log in to unmask]]
Sent: Monday, November 17, 2003 1:32 PM
To: [log in to unmask]
Subject: [TN] Gold 'bumps' on pads? How is it done?


Hi,
I am looking at a sample board done with 'gold bumps' in the centers of the
pads to allow surface to surface mounting of 2 boards. Anyone have a 'clue'
how this is done? How it gets used?
I have not seen this before and would like to learn about it.

Bill Brooks
PCB Design Engineer , C.I.D., C.I.I.

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